Head to a window maker. They also supply fly screens. Metal door jams so should be able to make a custom size screen door.

As an manufacturer of bifolding doors, this is always a discussion point with our clients - there are a range of choices Crimsafe make a bifolding security screen door - functions like a typical bifold but with the added security that only Crimsafe can offer There are retractable insect screens like Freedom, which we have used on several of our bifold installations, through ti Centor Or if you are really adventurous you would use an air curtain, above the bifold to deter the flies from coming in to the home at all (if you do a search for air curtains on google you will find a vast number, used extensive in commercial applications but creeping more and more in to our homes Enjoy your wide open space that your bifold will create - www.centralglass,net.au

Just done this - had stacker doors made to fit, could have had bifold however screens for bifold can't be crimsafe, so easily broken into or damaged by children or pets. We often leave the doors open at night with just the security screens locked. As ours are our front entrance and not the rear, security was important. Also bifold folding out without a wall or roof are open to the elements and can be damaged if open during a hi wind. Will weather quickly also. Bifold look great but you really need to decide if they need to have security screens etc. We had beautiful timber stackers made, as we get big winds occasionally and the bifolds would have folded out onto the deck with lots of sun - didn't want to be re lacquering every 6 months.

even more reason to do the new wall and door fame first and then the decoration is done last, but as you're replacing the frame and removing the tiles it could be a lucky opportunity to choose a door first then build the new frame to suit the door, then do the floors and then you'll probably have to resize the height of the doors to suit the precise new floor height and NB include the new fly screen door from the beginning so that the new frame suits both doors...best of luck but i have to say that the existing frame and gorgeous vintage glass with a simple plain new door with security screen and dark painted tile floors continued from outside to in would be my first choice